Recently, thin film transistor liquid crystal displays (TFT-LCDs) have been developed rapidly and used widely in various fields due to their advantages such as high quality of display, low power consumption, no radiation, etc. A One Drop Filling (ODF) method is usually adopted during the preparation of TFT-LCDs. In such a method, the cell process includes applying a sealant onto an array substrate or a color filter substrate, and then bonding the array substrate and the color filter substrate together in vacuum by high-accuracy alignment instruments, wherein glass fibers or silica beads are added into the sealant so as to make a cell gap. Thus, the sealant which bonds the two substrates and encloses the liquid crystal is vital for the cell process of the LCD preparation.
Conventional sealants are typically crosslinked by stepwise polymerization comprising an ultraviolet (UV) polymerization followed by a heat polymerization. During the UV polymerization, free radicals are produced from a photoinitiator in the sealant by UV irradiation, and then they initiate the polymerization of UV polymerizable monomers having carbon-carbon double bond to form a high molecular polymer. The polymerization rate of the UV polymerizable monomers having carbon-carbon double bond is relatively fast, and the volume shrinkage of the sealant during the polymerization is relatively large too. These factors can lead to problems such as a worse accuracy of alignment, and even an internal stress within the sealant which may influence the bonding strength.